C4a-Atomic Structure Flashcards
What are atoms?
Tiny particles of matter which make up everything in the universe
What does an atom include?
A nucleus surrounded by electrons
What charge does a nucleus have?
A nucleus is positively charged
What charge does an electron have?
An electron has a negative charge
What charge does an atom have?
An atom is neutral
What is a nucleus made up of?
Protons and neutrons
What is the relative charge and relative mass of an electron?
Electron charge: -1
Electron mass: 0.0005
What is the relative charge and mass of a proton?
Proton charge: +1
Proton mass:1
What is the relative charge and mass of a neutron?
Neutron charge: 0
Neutron mass: 1
Why is an atom neutral?
They have the same number of protons as electrons
What is the radius of an atom?
10-10m
What is the mass of an atom?
10-23g
What is an atomic number?
The number of protons in an atom
What is the mass number?
The total number of protons and neutrons in an atom
What are isotopes?
Varieties of an element that have the same atomic number but different mass numbers
What is an element?
Substances made up of only one type of atom
What was the order of the scientists which helped discover the structure of the atom?
Dalton
Thompson
Rutherford
Bohr
What was John Daltons theory?
Atoms are solid spheres and different spheres made up different elements
What was J.J Thompsons theory?
- Atoms were not solid spheres
- an atom must contain smaller, negatively charged particles (electrons)
What was the plum pudding model?
The atom had positively and negatively charged electrons dotted around inside it like plums in a pudding
What was Ernest Rutherfords theory?
The theory of the nuclear atom where there is a tiny positively charged nucleus at the centre, surrounded by a cloud of negative electrons and most of the atom is empty space
What was the gold foil experiment?
Scientists beamed alpha particles at very thin gold foil and as most particles passed through the foil, some particles unexpectedly were repelled and deflected back by a tiny concentration of positive charge in the atom.
What was Niels Bohr’s theory?
- all the electrons were contained in shells
- electrons can only exist in fixed orbits or shells
- each shell has a fixed energy
What did the Bohr model look like?
Electrons travel only in certain successively larger orbits around the nucleus. It was similar in structure to the solar system
